1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.geometry.euclidean.threed;
23
24 import java.util.ArrayList;
25 import java.util.List;
26
27 import org.hipparchus.exception.MathIllegalArgumentException;
28 import org.hipparchus.geometry.euclidean.oned.Interval;
29 import org.hipparchus.geometry.euclidean.oned.IntervalsSet;
30 import org.hipparchus.geometry.euclidean.oned.Vector1D;
31 import org.hipparchus.geometry.partitioning.Region.Location;
32
33 /** This class represents a subset of a {@link Line}.
34 */
35 public class SubLine {
36
37 /** Underlying line. */
38 private final Line line;
39
40 /** Remaining region of the hyperplane. */
41 private final IntervalsSet remainingRegion;
42
43 /** Simple constructor.
44 * @param line underlying line
45 * @param remainingRegion remaining region of the line
46 */
47 public SubLine(final Line line, final IntervalsSet remainingRegion) {
48 this.line = line;
49 this.remainingRegion = remainingRegion;
50 }
51
52 /** Create a sub-line from two endpoints.
53 * @param start start point
54 * @param end end point
55 * @param tolerance tolerance below which points are considered identical
56 * @exception MathIllegalArgumentException if the points are equal
57 */
58 public SubLine(final Vector3D start, final Vector3D end, final double tolerance)
59 throws MathIllegalArgumentException {
60 this(new Line(start, end, tolerance), buildIntervalSet(start, end, tolerance));
61 }
62
63 /** Create a sub-line from a segment.
64 * @param segment single segment forming the sub-line
65 * @exception MathIllegalArgumentException if the segment endpoints are equal
66 */
67 public SubLine(final Segment segment) throws MathIllegalArgumentException {
68 this(segment.getLine(),
69 buildIntervalSet(segment.getStart(), segment.getEnd(), segment.getLine().getTolerance()));
70 }
71
72 /** Get the endpoints of the sub-line.
73 * <p>
74 * A subline may be any arbitrary number of disjoints segments, so the endpoints
75 * are provided as a list of endpoint pairs. Each element of the list represents
76 * one segment, and each segment contains a start point at index 0 and an end point
77 * at index 1. If the sub-line is unbounded in the negative infinity direction,
78 * the start point of the first segment will have infinite coordinates. If the
79 * sub-line is unbounded in the positive infinity direction, the end point of the
80 * last segment will have infinite coordinates. So a sub-line covering the whole
81 * line will contain just one row and both elements of this row will have infinite
82 * coordinates. If the sub-line is empty, the returned list will contain 0 segments.
83 * </p>
84 * @return list of segments endpoints
85 */
86 public List<Segment> getSegments() {
87
88 final List<Interval> list = remainingRegion.asList();
89 final List<Segment> segments = new ArrayList<>(list.size());
90
91 for (final Interval interval : list) {
92 final Vector3D start = line.toSpace(new Vector1D(interval.getInf()));
93 final Vector3D end = line.toSpace(new Vector1D(interval.getSup()));
94 segments.add(new Segment(start, end, line));
95 }
96
97 return segments;
98
99 }
100
101 /** Get the intersection of the instance and another sub-line.
102 * <p>
103 * This method is related to the {@link Line#intersection(Line)
104 * intersection} method in the {@link Line Line} class, but in addition
105 * to compute the point along infinite lines, it also checks the point
106 * lies on both sub-line ranges.
107 * </p>
108 * @param subLine other sub-line which may intersect instance
109 * @param includeEndPoints if true, endpoints are considered to belong to
110 * instance (i.e. they are closed sets) and may be returned, otherwise endpoints
111 * are considered to not belong to instance (i.e. they are open sets) and intersection
112 * occurring on endpoints lead to null being returned
113 * @return the intersection point if there is one, null if the sub-lines don't intersect
114 */
115 public Vector3D intersection(final SubLine subLine, final boolean includeEndPoints) {
116
117 // compute the intersection on infinite line
118 Vector3D v1D = line.intersection(subLine.line);
119 if (v1D == null) {
120 return null;
121 }
122
123 // check location of point with respect to first sub-line
124 Location loc1 = remainingRegion.checkPoint(line.toSubSpace(v1D));
125
126 // check location of point with respect to second sub-line
127 Location loc2 = subLine.remainingRegion.checkPoint(subLine.line.toSubSpace(v1D));
128
129 if (includeEndPoints) {
130 return ((loc1 != Location.OUTSIDE) && (loc2 != Location.OUTSIDE)) ? v1D : null;
131 } else {
132 return ((loc1 == Location.INSIDE) && (loc2 == Location.INSIDE)) ? v1D : null;
133 }
134
135 }
136
137 /** Build an interval set from two points.
138 * @param start start point
139 * @param end end point
140 * @return an interval set
141 * @param tolerance tolerance below which points are considered identical
142 * @exception MathIllegalArgumentException if the points are equal
143 */
144 private static IntervalsSet buildIntervalSet(final Vector3D start, final Vector3D end, final double tolerance)
145 throws MathIllegalArgumentException {
146 final Line line = new Line(start, end, tolerance);
147 return new IntervalsSet(line.toSubSpace(start).getX(), line.toSubSpace(end).getX(), tolerance);
148 }
149
150 }